Type 1 diabetes (T1D) is a severe disease that has become more and more frequent already at a very early age. In type 1 diabetes the beta-cells of the pancreas are destroyed, which leads to insulin deficiency. The destruction of the beta-cells is believed to be caused by an autoimmune response, which in turn is assumed to be induced by a virus infection.
The connection between enteroviruses and T1D has been documented in a multitude of studies. Enteroviruses have been detected in the pancreas, blood and intestinal mucosa of patients with T1D more frequently than in control subjects and prospective studies have supported their role in the initiation of the beta-cell damaging process associated with T1D. Enteroviruses infect pancreatic beta-cells in cell culture and cause diabetes in animal models. Enterovirus vaccines have therefore been suggested for preventing T1D. However, the knowledge of which enterovirus serotypes that are involved in the disease is limited.
The group of enteroviruses includes more than 100 different serotypes, and because a vaccine covering all the 100 enterovirus serotypes is not realistic using the current standard vaccine technologies, the knowledge of which serotypes are involved in T1D is critical for vaccine development. Enterovirus infections are usually subclinical, but they may also cause various kinds of diseases. For example polioviruses, coxsackie B virus (CBV), coxsackie A virus (CAV), and echovirus as well as numbered enteroviruses are enteroviruses known to be involved in the development of a variety of diseases. For example Lee et al., 2007, Arch Virol, 152:963-970 analyzed clinical isolates from aseptic meningitis patients, and found that CBV5 was the most predominant strain. In addition CBV1, CBV3 and echovirus 9 were identified.
The spectrum of responsible serotypes varies a lot from disease to disease, and even in one disease like T1D the exact serotypes have not been fully and reliably identified. Indeed, previous studies reporting association between enteroviruses and T1D were not able to discriminate between serotype or were restricted to case reports. Some studies have suggested that a particular CBV serotype may be important (Yoon et al, 1979 New Eng J of Med, v 300, p 1173; Hindersson M, et al., 2005, J Clin Virol v.33 p 158; Dotta F. et al., 2007, PNAS 104: 5115; US2010/0047273 (Rappuoli et al.)). However, other than CBV enteroviruses have also been sporadically reported (Cabrera-Rode et al., 2003, Diabetologia; Williams et al., 2006, J Clin Micro v.44 p 441).
Klemola et al., 2008, Immunology of Diabetes V: Ann. N.Y. Acad. Sci 1150:210-212 analyzed sewage samples for non-polio enteroviruses. The most commonly detected serotypes were CBV1-5, Echo6, 7, 11, 25 and 30. They were tested for islet tropism. All serotypes were found to be destructive. No evidence suggesting that only certain enterovirus serotypes should be considered potentially diabetogenic was found.
WO01/00236 (Hyöty et al.) suggests the use of oral poliovirus in a vaccine against T1D. In addition it suggests another diabetes vaccine comprising one or more inactivated non-polio enteroviruses selected from the group consisting of CBV serotypes 1, 2, 3, 4, 5 and 6, echovirus serotypes 3, 4, 6, 9, 11, 22 and 30, CAV serotypes 9 and 16. However, no data is given as to the role of the individual serotypes listed. The immune response obtained by OPV, which is a live attenuated vaccine was believed to induce a T-cell mediated cross-reactive immune response, whereas the inactivated vaccine was believed to be serotype specific.
Despite a lot of investigation, there is still a great need for developing effective means and methods for preventing and treating type 1 diabetes. Embodiments of the present invention meet these needs.